There is known a thermoplastic elastomer composition prepared by dispersing a specific rubber elastomer component as a discontinuous phase in a specific thermoplastic resin matrix and has a good balance between air permeability resistance and flexibility (JP 8-259741 A).
In addition, a thermoplastic elastomer composition having more flexibility and excellent air permeability resistance by attaining a high elastomer component ratio by setting a melt viscosity (ηm) of a thermoplastic resin component, a melt viscosity (ηd) of an elastomer component in a thermoplastic elastomer composition and a solubility parameter difference (ΔSP) between the elastomer component and the thermoplastic resin component such that they satisfy a specific relational expression, as well as a pneumatic tire in which the thermoplastic elastomer composition is used for a gas permeation preventive layer is known (JP 10-25375 A).
Furthermore, there is also known a thermoplastic elastomer composition in which gas permeability resistance is greatly improved due to the presence of a barrier resin composition having a phase structure dispersed flatly in a thermoplastic elastomer having a continuous phase of a thermoplastic resin and a dispersion phase of a rubber composition, and moreover, which has flexibility, oil resistance, cold resistance and heat resistance (JP 10-114840 A).
Furthermore, there is also known a thermoplastic elastomer composition in which an acid anhydride-modified ethylene-based modifier polymer is blended in an aliphatic polyamide resin modified with a layered silicate (JP 2000-160024 A).